Epitaxial Chamber Pyrometer Feedback for Wafer Thermal Uniformity
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Solution Overview
Problem
The challenge in semiconductor manufacturing is achieving uniform temperature and thickness distribution of films across a wafer during epitaxial growth, which is crucial for precise processing and reducing manufacturing defects.
Innovation Solution
A system with frontside and backside pyrometers in an epitaxial growth chamber measures thermal radiation to estimate real-time temperature and thickness distributions, using a feedback control system to modulate heating source power and gas flow for precise control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If multiple pyrometers are used to measure temperature at multiple points, then temperature uniformity control is improved, but device complexity increases
Solution Approach 1:
The measurement system is segmented into multiple independent pyrometers positioned at different locations (center and edge) of the wafer. Each pyrometer independently measures temperature at its specific location, allowing the system to capture temperature distribution across the wafer surface without requiring a single complex measurement device.
Solution Approach 2:
The pyrometers serve multiple functions: they measure both the wafer temperature and the film temperature simultaneously. By comparing measurements from multiple pyrometers, the system also determines temperature uniformity and film thickness, making the measurement system multi-functional and reducing the need for separate measurement devices.
2Manufacturing precision
If real-time temperature monitoring is implemented, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The system implements real-time feedback control by continuously monitoring temperature measurements from multiple pyrometers and automatically adjusting the heating element power accordingly. The controller receives temperature data, compares it to target values, and modifies heating power in real-time to maintain precise temperature control, enabling manufacturing precision without requiring overly complex manual control systems.
Solution Approach 2:
The patent replaces complex mechanical temperature control mechanisms with a combination of optical measurement (pyrometers) and electronic control. Instead of using mechanical adjustments or complex thermal management hardware, the system uses non-contact optical temperature sensing coupled with electronic feedback to achieve precise temperature control.
3Manufacturing precision
If feedback control is used to adjust heating power, then film thickness uniformity is improved, but device complexity increases
Solution Approach 1:
The system uses feedback control where temperature measurements from pyrometers are continuously fed back to the controller, which adjusts heating element power in response to temperature variations. This feedback loop ensures that temperature remains uniform across the wafer surface, which directly translates to uniform film thickness during deposition processes.
Solution Approach 2:
The system dynamically changes the power parameter of the heating elements based on real-time temperature measurements. By adjusting the electrical power input to different heating zones, the system compensates for temperature non-uniformities and maintains optimal conditions for uniform film growth, achieving thickness uniformity through parameter optimization.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables in-situ, real-time monitoring and uniformity of temperature and thickness across the wafer, reducing defects by dynamically adjusting heating and gas processes.
Implementation Method 1
Pyrometers are often used to measure temperatures of films and wafer surfaces in a semiconductor processing chamber
Data Source
AI summary
In an embodiment, an apparatus includes a first pyrometer and a second pyrometer configured to monitor thermal radiation from a first point and a second point on a backside of a wafer, respectively, a first heating source in a first region and a second heating source in a second region of an epitaxial growth chamber, respectively, where a first controller adjusts an output of the first heating source and the second heating source based upon the monitored thermal radiation from the first point and the second point, respectively, a third pyrometer and a fourth pyrometer configured to monitor thermal radiation from a third point and a fourth point on a frontside of the wafer, respectively, where a second controller adjusts a flow rate of one or more precursors injected into the epitaxial growth chamber based upon the monitored thermal radiation from the first, second, third, and fourth points.